I have a Silver Century Plus number WSPCL139ee5.
This engine has good compression, and starts well. It it is run anywhere near maximum rpm after a few seconds the revs drop and it stutters, as if it has fuel starvation. If the throttle is closed slightly for a few seconds and then re opened it revs out cleanly, but then starts to stutter again. I have completely rebuilt the amal carb and also tried a spare and I have also swapped the wipac coil and points with another engine but with no luck. Could this be a head gasket
Any advice would be greatly appreciated.
Many thanks
wells01
Silver century plus loses power
Moderators: John@sos, charlesp, Charles uk, RickUK, Petergalileo
Does sound very much like the mixture is out as you have obviously considered yourself as you rebuilt the carb. As that didn't work and a replacement doesn't fix it then I can only surmise you have an air leak somewhere, or possibly a loose ignition backplate putting the timing out a bit.
If the backplate is fine check all the barrel, crankcase and head nuts are tight and the ones holding on the drive tube, if they are then you could try smearing some heavy grease over the outside of the joints one at a time to see if that gives a temporary improvement and show you where your problem lies.
I am assuming you are using the correct oil / petrol mix of course .... Your motor being made in 1975 would originally have left the factory set for a 10:1 mix but it can be converted to run on 25:1 see the FAQ on the main site for details of the conversion and ensure you are using the correct mixture for the carb set up
If the backplate is fine check all the barrel, crankcase and head nuts are tight and the ones holding on the drive tube, if they are then you could try smearing some heavy grease over the outside of the joints one at a time to see if that gives a temporary improvement and show you where your problem lies.
I am assuming you are using the correct oil / petrol mix of course .... Your motor being made in 1975 would originally have left the factory set for a 10:1 mix but it can be converted to run on 25:1 see the FAQ on the main site for details of the conversion and ensure you are using the correct mixture for the carb set up
Silver century plus loses power
Thanks for your replies. I have completely overhauled the fuel system and there is a good flow of clean fuel into the floatbowl. I am starting to suspect the head gasket as there seems to be a lot of rust around the gasket joint. I shall tighten all the bolts and grease the joints and see if there is any improvement.charlesp wrote:I would strongly advise a thorough cleaning of the fuel filter in the tap, the fuel line, and another check of the fuel filter in the banjo.
Regards
wells01